Stress distribution on a valgus knee prosthetic inclined interline -- a finite element analysis.

Total knee arthroplasty following valgus deformity is a challenging procedure due to the unique set of problems that must be addressed. The aim of this study is to determine, with a finite element analysis, the load distribution for an inclined valgus prosthetic balanced knee and to compare these results with those of a prosthetic balanced knee with an uninclined interline. Computational simulations, using finite element analysis, focused on a comparision between load intensity and distribution for these situations. We studied valgus inclination at 3 and 8 degrees. We noticed that for an inclination of 3 degrees, the forces are distributed almost symmetrically on both condyles, similar to the distribution of forces in the uninclined interline case. The maximum contact pressure is greater, increasing from 15 MPa to 19.3 MPa (28%). At 8 degrees of inclination, the contact patch moved anterolateraly on the tibia, meaning that the tibial condyles will be unequally loaded. The maximum contact pressure increases to 25 MPa (66%). These greater forces could lead to polyethylene wear and collapse. Additional tibial resection could be a useful method for balancing in severe valgus knee, when valgus inlination does not exceed 3 degrees.

Lead-Free Piezoelectric (Ba,Ca)(Zr,Ti)O3 Thin Films for Biocompatible and Flexible Devices.

In this work, we report the synthesis of functional biocompatible piezoelectric (1 - x)Ba(Ti0.8Zr0.2)TiO3-x(Ba0.7Ca0.3)TiO3, x = 0.45 (BCZT45), thin films with high piezoelectric properties. Pulsed-laser-based techniques, classical pulsed-laser deposition and matrix-assisted pulsed-laser evaporation, were used to synthesize the BCZT45 thin films. The second technique was employed in order to ensure growth on polymer flexible Kapton substrates. The BCZT45 thin films grown by both techniques show similar structural properties and high piezoelectric coefficient coupling between the mechanical loading and electrical potential. While it has long been shown that the electrical potential favors biological processes like osteogenesis, the assessment of cell adhesion and osteogenic differentiation onto BCZT materials has not yet been demonstrated. We prove here for the first time that BCZT 45 coatings on Kapton polymer substrates provide optimal support for osteogenic differentiation of mesenchymal stem cells in the bone marrow.

Feasibility Study of a Novel Navigation System for Biopsy of Peripheral Lesions in the Lungs.

A novel system for electromagnetic navigation in bronchoscopy (ENB) to improve peripheral lesion targeting and diagnostic is currently under development, and preliminary tests on a complex phantom are presented in this paper. The system named Transbite is proving to be easy to use, accurate and useful for experienced and beginner users, with precision around 5-9 mm in reaching targets in sub-segmental bronchi where a conventional video-bronchoscope cannot extent. Transbite system consists of a planning and orientation software, a navigation and biopsy forceps, an active marker that is placed on patient chest and an electromagnetic tracking system from the market connected to a computer containing the software. Transbite can be used with any bronchoscopy system, has a short set-up procedure and learning curve.

[Pressure stress in glaucoma--assessment through classical techniques and computational modelling]. / Stresul presional in glaucom--explorare prin tehnici clasice si modelare computationala.

UNLABELLED: Even if glaucoma remains a major eye illness with unknown etiology, the importance of vascular factors associated with mechanical factors contributing to the pathogenesis and development of glaucomatous optic neuropathy has been emphasized. the objective of the study consists in elaboration of a biomechanical model of the human eye correlated with clinical and ultrasonography evaluations aiming to early identification of changes induced by pressure stress in open angle glaucoma (OAG) at retrobulbar arteries and optic nerve head level. METHOD AND MATERIAL: The present study included a lot formed by 97 patients without glaucoma, aged 20-75 years (lot 1) and a lot formed by 71 patients with open angle glaucoma, aged 45-80 years (lot 2). We used usual methods in ophthalmological examinations and diagnosis (bottom ocular fundus examinations eye examinations, visual - field examinations, measurements of PIO), ultrasonography methods (CDI, pulsed Doppler, spectral Doppler and power-angio), computational modelling methods for ocular structures. RESULTS AND CONCLUSIONS: In open angle glaucoma color Doppler imaging shows changes in retrobulbar hemodynamic for most of the studied cases, ultrasonography techniques being considered as an important tool for the diagnosis and progression control in glaucomatous damage. Limitations of ultrasonography techniques consist of early identification of these alterations and can be improved by the elaboration of a biomechanical model of the human eye that will permit an abstraction and generalisation of the hemodynamic aspects with the aim of simulation of changes induced by high intraocular pressure on retrobulbar arteries level, the possibility of viewing these changes in their dynamics (on lower pressure values than 30 mmHg).